In the next generation of broadband cellular mobile communication system (IMT-Advanced), a base station (eNB) centered communication is limited due to, e.g., the problems of coverage performance and capacity of eNB and so on. With the rapid increase in requirement from various multi-media communications such as high-rate data service including local broadcast, inter-group instant high-density data communication, exchange of a large amount of information and the like, the capacity and frequency spectrum in the conventional communication manner has approached the upper limit. In a future wireless cellular network, the battery usage time of a mobile handheld terminal performing communication depends on the power usage efficiency, and the communication rate under a limited frequency spectrum resource depends on the frequency spectrum efficiency. How to balance the power usage efficiency and the frequency spectrum is an issue mainly researched for the current mobile communication systems.
D2D communication between terminals is a new technology in which terminals communicate directly with each other by multiplexing resources within a cell to improve the total performance of the system. Introducing D2D technology into the evolution of IMT-advanced may leads to an improved network structure, an enhanced coverage and an increased system capacity. D2D communication will bring about a series of improvements and optimizations on the original system. D2D communication has the following advantages: the system capacity is improved, the frequency spectrum is multiplexed to improve the frequency spectrum usage efficiency, the scarcity of available frequency resource is remitted, a load pressure on an eNB from a short-distance intensive data communication is reduced, a rapid resource management with higher time-frequency resolution can be satisfied by reduced control channels, as well as improved network structure, enhanced coverage, improved user fairness, improved wireless network service quality, consolidated lower structure, development of new type of services and the like.